Field programmable gate arrays using resistivity-sensitive memories

ABSTRACT

Field programmable gate arrays using resistivity-sensitive memories are described, including a programmable cell comprising a configurable logic, a memory connected to the configurable logic to provide functions for the configurable logic, the memory comprises a non-volatile rewriteable memory element including a resistivity-sensitive memory element, an input/output logic connected to the configurable logic and the memory to communicate with other cells. The memory elements may be two-terminal resistivity-sensitive memory elements that store data in the absence of power. The two-terminal memory elements may store data as plurality of conductivity profiles that can be non-destructively read by applying a read voltage across the terminals of the memory element and data can be written to the two-terminal memory elements by applying a write voltage across the terminals. The memory can be vertically configured in one or more memory planes that are vertically stacked upon each other and are positioned above a logic plane.

FIELD OF THE INVENTION

The present invention relates to programmable devices and specificallyto Field Programmable Gate Arrays Using Resistivity-Sensitive Memories.

BACKGROUND

A field programmable gate array (FPGA) is a programmable logic devicethat allows a user to design custom logic circuits for desired tasks. Auser can create a program for a desired task, transfer the program to anFPGA, and use the programmed FPGA to execute the desired task. CertainFPGAs can be reprogrammable, and allow for flexibility when creating ortesting device designs.

FPGAs typically include a memory to provide functions for logic gatesfor implementing the program. Several different types of memories may beused with an FPGA, including write-once and reprogrammable memories.Write-once memories include memories using fuse technologies, whichdestroy or establish a physical connection during writing, and thereforecannot be rewritten. Fuse technologies are non-volatile and retain theircontents when power is removed from the FPGA, but must be discarded if anew or updated program is desired.

FPGAs may also use reprogrammable memories such as random accessmemories (RAMs) including static RAMs (SRAMs). SRAMs can bereprogrammed, but lose their contents when power is removed from theFPGA. Since SRAMs are volatile, FPGAs incorporating SRAMs must be bootedwhenever they are powered up to provide functions to the memories.

There are continued efforts to improve the implementation of FPGAs.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention are disclosed in the followingdetailed description and the accompanying drawings. Although theDrawings depict various examples of the invention, the invention is notlimited by the depicted examples. Furthermore, the depictions are notnecessarily to scale:

FIG. 1A illustrates a field programmable gate array (FPGA) according toan embodiment;

FIG. 1B illustrates a programmable cell according to an embodiment;

FIG. 1C illustrates signal routing within an FPGA according to anembodiment;

FIG. 2 illustrates an FPGA including a boot memory for programming theFPGA according to an embodiment;

FIG. 3 illustrates an integrated circuit including an FPGA according toan embodiment;

FIG. 4A illustrates an FPGA using a vertically configured memoryaccording to an embodiment;

FIG. 4B illustrates an FPGA having vertically configured cell memoriesaccording to various embodiments; and

FIG. 4C illustrates an FPGA including vertically configured cellmemories and an extended memory according to various embodiments.

DETAILED DESCRIPTION

A detailed description of one or more examples is provided below alongwith accompanying figures. The detailed description is provided inconnection with such examples, but is not limited to any particularembodiment. The scope is limited only by the claims and numerousalternatives, modifications, and equivalents are encompassed. Numerousspecific details are set forth in the following description in order toprovide a thorough understanding. These details are provided for thepurpose of example and the described embodiments may be implementedaccording to the claims without some or all of these specific details.For the purpose of clarity, technical material that is known in thetechnical fields related to the embodiments has not been described indetail to avoid unnecessarily obscuring the description.

According to various embodiments, field programmable gate arrays (FPGAs)using non-volatile rewritable memories including a resistivity-sensitivememory element are disclosed. The FPGAs may include one or moreprogrammable cells that include a memory and a configurable logic. Thememory may include a resistivity-sensitive memory element that isnon-volatile and rewritable. The memory stores functions for theconfigurable logic. Since the memory is non-volatile, the FPGA retainsits contents when power is removed and the FPGA may be powered onwithout booting. Since the memory is rewritable, the FPGA can bereprogrammed.

Memory Technology

Non-volatile memory technologies may be used with memory systems todevelop high density, low cost, and fast access memories. Access mayrefer to accessing and performing data operations (e.g., read, write,erase) on a memory or memory array, such as those developed by UnitySemiconductor, Inc. of Sunnyvale, Calif., which providevertically-configured cell arrays (e.g., vertically-stacked,cross-point, two or three-terminal, non-volatile memory arrays) withreduced die sizes and manufacturing costs and system-levelfunctionality. Examples of memory arrays may include vertically-stacked,two or three-terminal, cross-point memory arrays, such as thosedescribed in U.S. patent application Ser. No. 11/095,026, filed Mar. 30,2005, U.S. Published Application No. 2006/0171200, and titled “MemoryUsing Mixed Valence Conductive Oxides,” hereby incorporated by referencein its entirety and for all purposes, describes two terminal memorycells that can be arranged in a cross point array. The applicationdescribes a two terminal memory element that changes conductivity whenexposed to an appropriate voltage drop across the two terminals. Thememory element includes an electrolytic tunnel barrier and a mixedvalence conductive oxide. The voltage drop across the electrolytictunnel barrier causes an electrical field within the mixed valenceconductive oxide that is strong enough to move oxygen ions out of themixed valence conductive oxides and into the electrolytic tunnelbarrier. Oxygen depletion causes the mixed valence conductive oxide tochange its valence, which causes a change in conductivity. Both theelectrolytic tunnel barrier and the mixed valence conductive oxide donot need to operate in a silicon substrate, and, therefore, can befabricated above circuitry being used for other purposes (such asselection circuitry).

The two-terminal memory elements can be arranged in a cross point arraysuch that one terminal is electrically coupled with an x-direction lineand the other terminal is electrically coupled with a y-direction line.A stacked cross point array consists of multiple cross point arraysvertically stacked upon one another, sometimes sharing x-direction andy-direction lines between layers, and sometimes having isolated lines.When a first write voltage V_(W1) is applied across the memory element,(typically by applying ½ V_(W1) to the x-direction line and ½−V_(W1) tothe y-direction line) it switches to a low resistive state. When asecond write voltage V_(W2) is applied across the memory element,(typically by applying ½ V_(W2) to the x-direction line and ½−V_(W2) tothe y-direction line) it switches to a high resistive state. Typically,memory elements using electrolytic tunnel barriers and mixed valenceconductive oxides require V_(W1) to be opposite in polarity from V_(W2).

Fast accesses for data operations may be achieved by using page buffersto allow multiple data operations to be performed substantiallysimultaneously (i.e., buffering data from a read and a write access).Further, various embodiments of data packet formats and datacommunication protocols may be used to indicate how data from differentdata operations (e.g., read, write) may be aligned to allow fastaccesses to a memory array.

The memory technology described above therefore comprises aresistivity-sensitive memory element according to an embodiment, whichmay be a two- or three-terminal memory element. Theresistivity-sensitive memory element detects changes in resistance in amemory element as either a 0 or a 1 bit, as is described in theabove-referenced U.S. patent. The memory technology is alsonon-volatile. In other words, when power is removed from the memory, thememory retains its contents. The memory technology requires no refresh,which improves performance over other memory technologies. The memorytechnology also requires no erase for writes and does not require anoperating system (OS), improving performance. Additionally, the memoryelements are physically smaller than many other memories, increasingdensities leading to smaller sizes and reduced power consumption. Thememory arrays can also be stacked on top of one another in a verticalmanner for increased density.

A Field Programmable Gate Array

FIGS. 1A-1C illustrate several views of a Field Programmable Gate Arrayaccording to various embodiments. An FPGA is a programmable logic devicethat can be programmed using appropriate software or other programmingtools. An FPGA may be programmed to perform a desired function, and mayinclude various components to facilitate that ability. For example,FPGAs may include several interchangeable blocks that may provide ageneric function, such as a programmable cell having a set of logicgates. The blocks may then be individually programmed to perform aspecific function. The various blocks may have various functions, which,when performed together, result in the execution of the desired task.

According to various embodiments, an FPGA may use the memory technologydescribed above. According to certain embodiments that are explainedbelow, the memory technology may be used as a boot memory that isnon-volatile, thereby retaining the programming of the FPGA when poweris removed. The boot memory may be used to program a conventional memory(such as a static random access memory (SRAM)) that provides functionsfor a configurable logic. According to another embodiment, theconventional memory is replaced with the non-volatile rewriteable memory(i.e., a memory including a resistivity-sensitive memory element such asthe memory technology described above.) According to this embodiment,the FPGA can be started and be functional without booting.

FIG. 1A illustrates an FPGA according to an embodiment. An FPGA 100 mayinclude a plurality of interconnected macro blocks 101. A block is anindividual component that can be incorporated into an FPGA design andmay be pre-designed to facilitate the creation of the FPGA. An FPGA mayinclude several different types of blocks, for example memories,processor cores, and logic blocks. A macro block such as one of themacro blocks 101, may be a larger block created from other, smallerblocks. The FPGA 100 includes a plurality of programmable cells 102 thatmay be macro blocks 101. The programmable cells 102 may be macro blocksof any of various designs and may include logic and memory blocks, aswill be explained when discussing FIG. 1B.

FIG. 1B illustrates a programmable cell 102 according to an embodiment.The programmable cell 102 may be a macro block including other blockssuch as a cell memory 104, a configurable logic 106, and input/output(I/O) logics 108. These components in combination create a programmablecell 102 that can be programmed with various functions, thereby enablingthe FPGA 100. The programmable cell 102 is an example of a macro blockfor an FPGA; it is understood that various other macro blocks may becreated as desired by a user of the FPGA 100.

The cell memory 104 may store functions for the configurable logic 106.The functions may, according to an embodiment, be a look-up tableincluding various functions capable of controlling the configurablelogic 106. According to an embodiment, the cell memory 104 may be anon-volatile rewriteable memory including a two-terminalresistivity-sensitive memory element such as the memory technologydescribed above. According to another embodiment, the cell memory 104may be a volatile memory such as an SRAM.

According to various embodiments, the non-volatile rewritable memoryusing the memory technology described above may be used to performmemory emulation. In this context, “emulation” refers to using the cellmemory 104 to perform the function of one or more previously used memorytypes. For example, the memory cell 104 may perform the function of aSRAM. In this instance, the memory cell 104 may be said to be performing“SRAM: emulation.” However, unlike SRAM which is volatile, the memorycell 104 emulates SRAM and is non-volatile (i.e., stored data isretained in the absence of power).

If the cell memory 104 is a non-volatile rewritable memory, the FPGA 100can be initially programmed, and thereafter be powered on withoutbooting (i.e., without having to load lookup tables or other functionsfrom an external boot memory). This behavior is hereinafter referred toas “instant-on.” Further, the cell memory 104 can be rewritten to changethe program of the FPGA 100.

The FPGA 100 may also be programmed using an internally added bootmemory, which is described further regarding FIG. 2. The boot memory mayprovide the lookup tables or functions to the cell memory 104 duringbooting of the FPGA 100. If the cell memory 104 is a volatiletechnology, such as SRAM, the boot memory provides the functionswhenever the FPGA 100 is powered on. According to an embodiment, if thecell memory 104 is non-volatile, such as the memory technology describedabove, a boot memory may be used to provide initial lookup tables orfunctions when the cell memory 104 is unprogrammed. According to thisembodiment, after the initial programming, the FPGA 100 may be poweredon without booting. The uninitialized memory may be programmed via aserial port using a tester, a processor, or prior to insertion into theprinted circuit board (PCB).

The configurable logic 106 may comprise several programmable gates asmay be appropriate for a specific application. The configurable logic106 receives signals from the cell memory 104 for performing variouslogic functions as designated by a user of the FPGA 100. Theconfigurable logic 106 may be a group of logic gates, or may be aspecialized block such as a processor core or a digital signal processor(DSP).

The I/O logic 108 is a block used to provide communication betweenprogrammable cells 102 and other macro blocks 101. The FPGA 100 mayinclude several macro blocks 101 and programmable cells 102, and the I/Ologic 108, along with other routing components (that are described inFIG. 1C), allow one macro block (e.g., one programmable cell) tocommunicate with other blocks (or cells).

According to another embodiment, macro blocks 101 other than theprogrammable cells 102 may be included in the FPGA 100. The macro blocks101 may include macro blocks with or without memories, or with orwithout configurable logics. The macro blocks 101 may include variouslogics that can be used to perform specialized functions for the FPGA100.

FIG. 1C illustrates one example of signal routing within an FPGAaccording to an embodiment. The FPGA 100 may include severalprogrammable cells 102 that perform specified logic functions asdesignated by the FPGA's 100 current program. The programmable cells 102communicate with one another to facilitate the operation of the logicprograms of the FPGA 100. Various routing components are placed betweenthe programmable cells 102 to facilitate this communication.

Switches 110 may include various components, such as multiplexers andAND gates, that direct signals between the programmable cells 102. Theswitches 110 are connected to other switches 110 and the programmablecells 102 through communication lines 112. The switches 110 may beprogrammed using, for example, the boot memory described above oranother programming technique to designate the proper routing betweenthe programmable cells 102.

The switches 110 may include one or more registers 114 (or other memoryelements) that stores switching and routing information for the FPGA100. The switches 110 can be used to redirect traffic between theprogrammable cells 102 of the FPGA 100. The routing information may beparticular to a program of the FPGA 100, and may be used to implement adesired function of the FPGA 100. For example, the routing informationmay direct the output of one programmable cell 102 to anotherprogrammable cell 102. The second programmable cell may use theinformation from the first to perform its designated function.

Each switch 110 may store different routing information based on thecurrent program of the FPGA 100. The registers 114 may be conventionalregisters or registers having a resistivity-sensitive memory element(e.g., a two-terminal memory element) such as those described in U.S.patent application Ser. No. 12/005,685, filed on Dec. 28, 2007, USPublished Application No. 2009/0172350, and titled “Non-VolatileProcessor Register.”, which is herein incorporated by reference for allpurposes. If the registers 114 use the memory technology describedabove, the registers 110 are non-volatile and allow instant-on of theFPGA 100 when used with a non-volatile memory 102. It is understood thatother types of routing, including using different switches and differentpaths, may be used with the various embodiments described herein, andthat other macro blocks 101 may be also be including included in therouting scheme of the FPGA 100.

FPGA Implementations

FIG. 2 illustrates an FPGA including a boot memory for programming theFPGA according to an embodiment. An FPGA 200 includes an FPGA structure202 with additional components. The FPGA structure 202 may be, forexample, the FPGA 100 described above, which may include one or moremacro blocks (e.g., the programmable cells 102). The FPGA structure 202may also be any other type of FPGA structure, such as those that arecommercially available. The FPGA 200 may be housed on an integratedcircuit or in another circuit package.

Connected to the FPGA structure 202 is a boot memory 204. The bootmemory 204 stores functions for the FPGA 200 upon booting. The bootmemory 204, according to an embodiment, uses the memory technologydescribed above, including a non-volatile rewritable memory having aresistivity-sensitive memory element. According to this embodiment,because the boot memory 204 is non-volatile, the FPGA 200 can beprogrammed initially and then booted without external support from otherdevices. Further, according to an embodiment, the memory may have avertical configuration, which can integrate the boot memory 204 into theFPGA 200 without increasing the physical footprint of the FPGA 200.

An interface 206 and a sequencer 208 provide write data 210 and memoryaddresses 212 for the boot memory 204, respectively. The interface 206and the sequencer 208 are used to program or reprogram the boot memory204. The interface 206 receives write data from external devices such asprogramming devices, and can be used to receive functions for the FPGA200. The sequencer 208 provides sequential memory addresses to populatethe boot memory 204 with the received functions. According to anembodiment, the interface 206 and the sequencer 208 are used wheninitially programming the FPGA 200. Since the boot memory 204 isnon-volatile, once the FPGA 200 has been programmed, the FPGA 200 canboot without receiving additional functions. The sequencer may also beused to transfer data from the boot memory 204 into the FPGA structure202 when the FPGA 200 is powered on.

According to another embodiment, the boot memory 204 may also be used asan external memory for the FPGA structure 202. The boot memory 204 maybe used to store data, such as look up tables, which are too large tostore in the internal memories (e.g., the cell memories 104) of the FPGAstructure 202.

FIG. 3 illustrates an integrated circuit (IC) including an FPGAaccording to an embodiment. An FPGA 300 includes an FPGA structure 302(e.g., the FPGA 100). The FPGA 300 also includes an interface 304, whichcommunicates with the FPGA structure 302 over at least one data line 306(two are depicted). The interface 304 directs data from external devicesto the FPGA structure 302. According to an embodiment, the FPGA 300 usesa non-volatile rewritable memory having a resistivity-sensitive memoryelement. Because the memory technology described above does not need anerase operation prior to a write operation, sequential write accesses ofthe memory is not needed, and the memory in the FPGA 302 can be accessedusing an interface (e.g., interface 304) without a sequencer.

An internal memory 310 may also be added to the FPGA 300 according toanother embodiment. The internal memory 310 can be used to store datathat is too large to be stored in the FPGA structure 302 (e.g., in thecell memories 104), or that may be needed by several different macroblocks of the FPGA structure 302. The internal memory 310 may also beused as a boot memory if so desired. The internal memory 310communicates with the FPGA structure over at least one data line 312.

According to an embodiment, the internal memory 310 is internal to anintegrated circuit including the FPGA 300 and may be used for memoryblock(s) for the FPGA 300. The internal memory 310 may be used asprogram store for imbedded processors or as memory elements in asequencer design or for look up tables required for some processes. Theinternal memory 310 may be vertically configured above the FPGAstructure 302 (see, e.g., FIG. 4C) and may be loaded through theinterface 304. The internal memory 310 may, according to variousembodiments, emulate SRAM, DRAM, Flash memory, or read only memory (ROM)in the system environment.

Vertically Configured Memories in FPGAs

FIGS. 4A through 4C illustrate FPGAs including vertically configuredmemories according to various embodiments. According to an embodiment,the memory technology described above may be configured so that an FPGAincluding memory of the memory technology and other semiconductordevices may be arranged into multiple vertically configured planes.Vertically configured planes allow for smaller die sizes, since thememory can be placed above the logic components. The configurationsshown here may be used with the FPGAs 100, 200, and 300 described above.

An IC may be configured so that logic comprising transistors and othersemiconductor devices, such as the logic used to access the memory(i.e., the memory logic), multiplexers, inverters, buffers, and otherdevices are formed on a semiconductor substrate (e.g., a silicon Siwafer) located in a base (or bottom) logic plane. The memory may then beformed above the logic plane in one or more vertically configuredplanes. Using these vertical configurations significantly reduces thefootprint of ICs created with this memory technology. FIGS. 4A through4C are examples of various configurations that may be implemented withthe FPGAs shown above in FIGS. 1A through 1C, FIG. 2 and FIG. 3.

FIG. 4A illustrates an FPGA using a vertically configured memory. TheFPGA 400 is an IC including three planes: a logic (or base) plane 402, afirst memory plane 404, and a second memory plane 406. Although twomemory planes 404 and 406 are shown, it is understood that any number ofmemory planes may be used, depending on the footprint of the logic plane402 and the amount of memory desired for the FPGA 400, as well as otherdesign considerations and application specific requirements. Accordingto an embodiment, the FPGA 400 may be used when a memory technologyother than the memory technology described above (e.g., SRAM) isincluded in the macro blocks (i.e., the cell memory 104) of the FPGA400. The FPGA 400 may also be used when the cell memories include anon-volatile rewriteable memory including a resistivity-sensitive memoryelement, according to other embodiments.

The FPGA 400 may be an IC that is constructed using a verticalconfiguration as described above regarding the disclosed memorytechnology. The base plane (e.g., the logic plane 402) of an IC using avertical configuration may contain logic, active circuitry, andsemiconductor elements, such as transistors and other components forminglogic gates and larger devices. The memory is then formed in one or moreplanes above the base plane, and controlled by memory logics in the baseplane. The memory is connected to the base plane using interconnectssuch as vias, plugs, contacts, and other interlayer connectionstructures, for example.

The base plane 402 includes logic 408 for programmable cells and theirassociated memories (e.g., the configurable logic 106 and the cellmemory 104). The memory may be, for example, an SRAM emulation or otheremulation of other memory types. According to an embodiment, the logic408 may include only the configurable logic, as the FPGA 400 may usememory in the memory planes 404 and 406 for implementing the logicfunction and providing the signals to drive the configurable logic.

The base plane 402 may also include an interface logic 410, a sequencerlogic 412, and a memory logic 414. The interface logic 410 and thesequencer logic 412 enable the interface 206 and the sequencer 208,described above. The memory logic 414 includes the components used toaccess the memory in the memory planes 404 and 406. The memory logic 414may be connected to the planes 404 and 406 using interconnects such asvias.

The memory planes 404 and 406 may be used as a boot memory such as theboot memory 204, or may, according to some embodiments, be used as thecell memory (e.g., the cell memory 104). The memory planes 404 and 406may also be used as an internal memory such as the internal memory 310.Any number of memory planes may be used with the FPGA 400 depending onthe specific application. Moreover, one or more memory planes (e.g.,memory planes 404 and 406) may be partitioned into sub-planes.

FIG. 4B illustrates an FPGA having vertically configured cell memoriesaccording to various embodiments. An FPGA 420 includes two planes: alogic plane 422, and a memory plane 424. The logic plane 422 includesseveral memory logics 426 that include components to control memory inthe memory plane 424. The memory plane 424 includes several individualcell memories 428 (e.g., the cell memory 104). The logic plane 422 mayalso include other logics and active circuitry, such as interface logicsor sequencer logics, shown above.

The memory in the memory plane 424 comprises a non-volatile rewriteablememory including a resistivity-sensitive memory element, such as thememory technology described above. The memory plane 424 is divided intoseveral individually accessed cell memories 428 to enable multipleprogrammable cells for the FPGA 420. Each of the cell memories 428 isindividually controlled by one of the memory logics 426. The cellmemories 428 may also be divided into additional planes if so desired,or additional planes may be added.

FIG. 4C illustrates an FPGA including vertically configured cellmemories and an extended memory according to various embodiments. AnFPGA 440 has three planes: a logic plane 442, a first memory plane 444and a second memory plane 446. The second memory plane 446 is anextended memory 460 that may be used to store additional data, such aslook up tables, which may be accessed by multiple programmable cells.The extended memory 460 can be used as additional cell memory fordesigns that may be too large for the existing cell memories in thefirst plane 444. The extended memory 460 in the second memory plane 446may alternatively or additionally be used as a boot memory, similar tothe boot memory 204, if so desired, or the extended memory 460 in thesecond memory plane 446 may perform both functions.

The logic plane 442, like the logic plane 422, includes memory logics448 that are used to control cell memories 450 in the first memory plane444. Additionally, the logic plane 442 includes another memory logic 452that may be used to control the extended memory 460 of the second memoryplane 446. The memory logic 452 may be connected to the second memoryplane 446 using vias routed through the first memory plane 444.

Although certain vertically configured memories are shown in FIGS. 4Athrough 4C, it is understood that various other configurations,including more or fewer planes, memory plane(s) partitioned into one ormore sub-planes, different locations of specific memories, etc., may beused as desired.

Although the foregoing examples have been described in some detail forpurposes of clarity of understanding, the invention is not limited tothe details provided. There are many alternative ways of implementingthe invention. The disclosed examples are illustrative and notrestrictive.

What is claimed is:
 1. A field programmable gate array (FPGA)comprising: a first configurable logic block formed in a substrate; afirst memory formed in at least one memory layer overlying the substrateand connected with the first configurable logic block, the first memorycomprising non-volatile resistive memory elements, the first memoryproviding signals to drive the first configurable logic block; and aninterface connected with the first memory and operative to provide writedata to the first memory; a second configurable logic block formed inthe substrate and a second memory formed in the at least one memorylayer overlying the substrate, the second memory connected with thesecond configurable logic block, the second memory providing signals todrive the second configurable logic block, and wherein the interfacefurther connects with the second memory and is operative to providewrite data to the second memory; and a third memory formed overlying thesubstrate and comprising non-volatile resistive memory elements, thethird memory providing data accessible to both the first and secondconfigurable logic blocks.
 2. A field programmable gate array (FPGA)comprising: a first configurable logic block formed in a substrate; asecond configurable logic block formed in the substrate; a first memoryformed in at least one memory layer located directly on a surface of thesubstrate and accessible to both the first and second configurable logicblocks, the first memory comprising non-volatile resistive memoryelements, the first memory providing signals to drive the one or both ofthe first and second configurable logic blocks; an interface connectedwith the first memory and operative to provide write data to the firstmemory; and further comprising a second memory formed in the at leastone memory layer overlying the substrate, wherein the second memory isconfigured as boot memory.
 3. A field programmable gate array (FPGA)comprising: a first configurable logic block formed in a substrate; asecond configurable logic block formed in the substrate; a first memoryformed in at least one memory layer overlying the substrate andaccessible to both the first and second configurable logic blocks, thefirst memory comprising non-volatile resistive memory elements, thefirst memory providing signals to drive the one or both of the first andsecond configurable logic blocks; an interface connected with the firstmemory and operative to provide write data to the first memory and atleast one memory layer comprises multiple memory layers; and a secondmemory formed in the at least one memory layer overlying the substrate,wherein the second memory stores additional information and provides theadditional information to the first memory.